Climate control is expensive. You should pay for electricity both for your fan and air heating, as well as for even more expensive air cooling and other treatment processes that might be required. There are meters available on the market for all consumed media (gas, water, electricity etc.), but not for the air in air-conditioning systems.
Thus lessors usually simply use an allocation formula based on the rented area: the total of spent energy is distributed between individual users according to the number of square metres rented by them, regardless of how much each of them has actually spent. Such method is not fair. It often causes retention of costs or legal disputes. Due to energy efficiency reasons and also because of the new directive German VDI 2077 Sheet 4, many lessors now begin to bill each individual tenant for energy actually spent by him.
Luftmeister GmbH attended to this application area and developed the worldwide first air meter and air energy meter. The air meter adds up cubic metres of air received by each user. The air energy meter also records quantities of heat and cold supplied to each user. So the high costs of air treatment can be fairly distributed between the users. For more information, see the technical article “Ventilation Cost Billing“.
This new directive (official draft as of January 2017, white print is probably available at the end of 2017) describes billing the ventilation cost according to actual use. The directive distinguishes between different cases. If a single ventilation and air conditioning system is shared by several renters and they receive individually controlled volume flows and/or the air is supplied to them during different times of day, the lessor is obliged to bill each of them for the air actually consumed. The full text of the directive can be purchased from the Beuth Publishing House.
This technical article deals with ventilation cost billing based on actual consumption by each user and illustrates it with the help of a numerical example: